Future nuclear power policy by countries should be based on science and not emotions after the crisis in tsunami-hit Fukushima last month, a top Japanese diplomat said.

"Experts from all the countries should sit and share their experiences for the future choice of nuclear power scientifically," Ambassador to India Akitaka Saiki said here while interacting with citizens of Mumbai at Observer Research Foundation last evening.

"The failure of Fukushima -- we have to look at it scientifically and not emotionally," he said adding "we have 54 reactors all located along the coast. If we have to shift these to some heights, we need to find easy access to water supply which is very essential."

Japan was always prepared for earthquakes and tsunami but not at this unprecedented level, said Saiki, who is on a three-day visit to Mumbai to interact with Indian industry leaders to promote trade and commerce between the two countries.

"We have been able to offer quality reactors but if needed our scientists and engineers will have no hesitation to learn from other countries," he added.

Saiki said the six reactors in Fukushima Daiichi, that accounted for 10 per cent of the electricity in Japan, will have to be decommissioned and added that alternate arrangement of power supply needed to be done.